Friction facing



j I To all whomalt may concern:

NoDrawing.

FREDERICK C. STANLEY, OF BRI DGEPORT, CONNECTICUT, ASSIGNOR TO RAYBESTOS COMPANY, OF IB RIDGEPORT. CONNECTICUT, A CORPORATION OF CONNECTICUT.

FRICTION .racme.

Be it known that I, F REDERIOK C. STAN- LEY, a citizen of the United States; residing in the city of Bridgeport, county of Fairfield, and State of Connecticut, have invented certain new and useful Improvements 7 in Friction Facings, of which the following is a specification.

This invention relates to improvements in friction facings and refers more particu-.

larly to a clutch facing or brake lining adapted for use in motor vehicles.

' The invention is directed to a novel" form of friction facing made from felted unwoven asbestos fibre saturated with a binder.

The object of the invention is toprovide a product which will have a maximum tensile strength and hardness so that it can withstand the shocks to which these facinp's are subjected in a motor car and also will have sufficient resistance to abrasion; while 'atthe sametime it has the proper co-efii- I in a suitable grinding machine or cutter.

The ground material is then put into a beater mixed with the .water or other solution and be ten into-a pulp. The pulp 15 then delivered to a paper making machine as for example a wet board machlne' andv formed into sheets or boardsof suitable of the product and also converts the binder into a form insoluble by oil or Water. It also tends to produce 'a uniform curing throughout the mass during the curing operation hereinafter described. It is to be Specificatiofiofletters Patent. Patented May 2, 1922, n plicationfiled September 24, 1919. Serial No. 325,912. v

.After the sheets or boards have been formed as described, they are subjected to hydraulic pressure in suitable presses and are then hung up to .dry in a drying room ofsuflicient temperature to remove the water. The sheet is then calendered to the desired thickness and the friction facings" are then cut out of the sheet. The sheets are subjected to suflicient pressure in the cal-' ender to obtaln as much tensile strength in the dry sheet as is feasible. 'The friction facings whether clutch rings or brake linmgs 'are now 'ready for saturation. The saturating tank is filled with a binder. This binder may consist of 94 per cent of linseed oil, 6 percent of gilsonite in solution in the 7 oil the mixture be'ingflthinned with gasoline to about 33 Baum gravity. The friction facings are then immersed while suspended on suitable rods in this binder solution for a period of half an hour. ings are then removed and put.in a closed steam oven and maintained at a temperature of about 200 F. to drive ofi the gasoline which gasoline may be recovered and saved This steam treatment is preferably continued from two to three hour-S. The friction facings are then removed toi a closed baking oven where they are subjected to a temperature of about 250 F., for a period of twelve hours. The facings are then taken out of the oven and immersed in another saturating tank containing a solution of 66 per cent of linseed oil and 33 per cent of gasoline; thegravity of the solution being about 33 Baum. takes place for from two to three minutes. In both of the saturating steps double boil linseed oil is preferable. The friction facings are then put into a second closed baking oven and maintained at a temperature of 300 F. for twenty fourhours. The heat in both of the baking ovens is preferably dry heat. The friction facmgs are then removed from the second oven and sand papered to micrometer size and to get a smooth finish to the facing. The facings are now ready for use.

I have given above an illustration in-which the product is manufactured by means of a process which is actually carried out in com- The friction fac- 80 This second immersion 95 mercial operation. It is to be understood that the temperature and length of treatment are subject to reasonable variations de pending on the flexibility and strength required in the finished product. Also oils other than linseed oil may perhaps in certain cases be used and other asphalts substituted for gilsonite.

During the baking operation, the linseed oil, due to the presence of the air in the oven and also to the oxidizing agent of the sheet, is oxidized to produce a tough hard binder. The solubility of the linseed'oil in gasoline before the baking treatments is practically 100%, while after the baking treatments, it is very materially reduced, and in fact, the baking operation may be so carried out as to make the oil practically insoluble in the gasoline. of the double saturation and double baking, a more eflicient curing of the binder is obtained and the sheet can be impregnated with larger quantities of binder. This addsgreatly to the tensile strength and hardnessof the finished product. In order that the tensile strength of the friction facings made in this manner may be more clearly understood, I submit the following, giving actual tests made on such friction facings:

Thickness of Thickness of average tensile Average hardshcet before sheet at t e r Strength of finness of finished calenderi ng calend ering ished facing in facing by Brinin inches. in inches. lbs. per sq. in. nell test.

It is to be noted that by means be taken to prevent the material from be-' ii coming so highly heated as to catch fire.

This exo-thermic reaction results in the fact that the oxidation is of such a character as to generate heat in addition to that externally applied. This exo-thermic reaction of oxidation is well known in other arts as for example in the manufacture of air blown asphalt from petroleum residuum.

The co-eificient of friction is not less than .3 when used dry on steel and not less than .2 when used wet on steel in certain of the products that I have made by this invention.

In my copending application Serial No. 325911, filed September 2 1, 1919, I have disclosed and claimed the process for making the present product.

I claim as my invention:

1. A friction facing formed of unwoven fibrous material containing an oxidized binder, and having a tensile strength in excess vof 1700 pounds per square inch.

2. A friction facing composed of unWoven fibrous material having a binder oxidized therein, said facing having a tensile strength of at least 3000 pounds to the square inch and a Brinnell hardness in excess of 15.

3. A friction facing composed of unwoven asbestos fiber impregnated with an oxidized binder substantially insoluble in mineral oils, said facing having a tensile strength exceeding 1700 pounds per square inch and a Brinnell hardness in excess of 15.

4. A friction facing composed of unwoven asbestos fiber containing an oxidized binder and a non-gaseous oxidizing agent, the binder being substantially insoluble in mineral oil, said facing having a tensile strength of at least 2000 pounds per square inch.

5. A friction facing composed of unwoven asbestos fiber containing an oxidized binder and a non-gaseous oxidizing agent, the binder being substantially insoluble in mineral oil, said facing having a tensile strength, of at least 2000 pounds per square inch, and

a Brinnell hardness inexces's of 15.

FREDERICK c. STANLEY. 

